The Ryukin Goldfish: The Golden Humpback

The beautiful Ryukin Goldfish are a Japanese version of the Fantail Goldfish. They were developed from the common Fantail Goldfish. Like their Fantail counterpart, they are one of the more rounded or egg-shaped fancy goldfish. The Ryukin Goldfish are easily differentiated from other fantail by their extremely high back, which is often described as a dorsal hump. The hump starts in the neck region and gives a more pointed appearance to the Ryukin's head, They also have a wider caudal fin than the Fantail. A distinguishing feature common to both the Fantail and the Ryukin Goldfish is?their split or double caudal (tail) fin.

All about the fantail family of fish

It is a member of the carp family, the Calico Fantail is generally quite hardy.
Does well in aquariums as well as backyard garden ponds .
It is an omnivore and will eat all types of dried and live foods.

For a fish to be considered the 'perfect' fantail, the tail fin needs to be completely split with the two lobes much closer together on top than on the bottom, making it look triangular when viewed from the back. Without this though, they'll still make awesome pets. Here's some features that'll make you buy the Calico fantail.

Easy to maintain freshwater aquarium fish
Make your aquarium look beautiful with these fish
Feeds on basic flake food
Civilized and peaceful. Will not attack other fish
Very hardy variety of fancy goldfish, a great option for the novice goldfish keeper.

Read more about fantail here: Link 1, Link 2, Link 3, Link 4